The present invention is directed to an endless flexible seamed belt wherein an image can be transferred at the seam of the belt with little or no print defects caused by the seam. In embodiments, the present invention relates to xerographic component imageable seamed belts comprising an adhesive formed between interlocking elements of a seam. In an embodiment, an overcoat, and preferably a polyvinylbutyral and isocyanate overcoat, or a polyurethane overcoat from the reaction of a polyvinylbutyral and isocyanate, is positioned over the imageable seamed belt. The present invention, in embodiments, provides a belt, which has low surface energy and low friction. The present invention further provides, in embodiments, a belt having a seam with increased strength. The present invention, in embodiments, also provides a belt in which an increase in toner transfer efficiency and a decrease or elimination of toner disturbance is possible, due to an improvement in controlled conductivity. The belt, in embodiments, further allows for improved cleaning because of the increased toner transfer efficiency. In embodiments, a cleanerless system is realized. The present invention further provides, in embodiments, a reduced energy consumption due, in part, to a decrease in necessary cure temperature. A broader latitude of seam adhesives can be used with the outer layer, and the outer layer is further inexpensive as an overcoat. The coating, in embodiments, has increased adhesion to substrate materials. The belt, in embodiments, allows for image transfer at the seam, which cannot be accomplished with known seamed belts.
In a typical electrostatographic reproducing apparatus such as an electrophotographic imaging system using a photosensitive member, a light image of an original to be copied is recorded in the form of an electrostatic latent image upon a photosensitive member and the latent image is subsequently rendered visible by the application of a developer mixture. One type of developer used in such printing machines is a liquid developer comprising a liquid carrier having toner particles dispersed therein. Generally, the toner is made up of resin and a suitable colorant such as a dye or pigment. Conventional charge director compounds may also be present. The liquid developer material is brought into contact with the electrostatic latent image and the colored toner particles are deposited thereon in image configuration.
The developed toner image recorded on the imaging member is transferred to an image receiving substrate such as paper via a transfer member. The toner particles may be transferred by heat and/or pressure to a transfer member, or more commonly, the toner image particles may be electrostatically transferred to the transfer member by means of an electrical potential between the imaging member and the transfer member. After the toner has been transferred to the transfer member, it is then transferred to the image receiving substrate, for example by contacting the substrate with the toner image on the transfer member under heat and/or pressure.
Transfer members enable high throughput at modest process speeds. In four-color photocopier or printer systems, the transfer member also improves registration of the final color toner image. In such systems, the four component colors of cyan, yellow, magenta and black may be synchronously developed onto one or more imaging members and transferred in registration onto a transfer member at a transfer station.
In electrostatographic printing and photocopy machines in which the toner image is transferred from the transfer member to the image receiving substrate, it is desired that the transfer of the toner particles from the transfer member to the image receiving substrate be substantially 100 percent. Less than complete transfer to the image receiving substrate results in image degradation and low resolution. Complete transfer is particularly desirable when the imaging process involves generating full color images since undesirable color deterioration in the final colors can occur when the color images are not completely transferred from the transfer member.
Thus, it is desirable that the transfer member surface has excellent release characteristics with respect to the toner particles. Conventional materials known in the art for use as transfer members often possess the strength, conformability and electrical conductivity necessary for use as transfer members, but can suffer from poor toner release characteristics, especially with respect to higher gloss image receiving substrates.
Polyimide substrate transfer members are suitable for high performance applications because of their outstanding mechanical strength and thermal stability, in addition to their good resistance to a wide range of chemicals. However, the high cost of manufacturing unseamed polyimide belts has led to the introduction of a seamed belt. Polyimides with the best mechanical and chemical properties often exhibit poor adhesion at the seam even when commercially available primers are used. Further, polyimide materials exhibit relatively high surface energy and high friction, which decrease toner transfer efficiency in transfix and transfuse applications. In order to have high toner transfer efficiency, higher electric fields are typically required to transfer the toner and various costly cleaning apparatuses are employed to remove residual toner that does not transfer. In addition, present imageable seam belt substrates such as polyimides have high surface resistivity, which reduces the electrical latitude of seam adhesives and causes toner disturbance. Meanwhile, the seam strength of imageable seams can be relatively low due to superfinishing of the seam area. These seams are fragile and may be easily damaged if mishandled.
Therefore, it is desired to provide a belt, which has the desired properties of the polyimide belt, but with low surface energy, low friction, and controlled conductivity. Such a belt will increase toner transfer efficiency, improve cleaning and consequently reduce the energy consumption. Further, it is desired to provide a belt, which has increased strength. Also, it is desirable to provide a belt, which works well with a broader latitude of seam adhesives. Moreover, it is desirable to provide a belt, which is relatively inexpensive. In addition, it is desirable to provide a seam, which is imageable, thereby reducing or eliminating the presence of print or copy defects.
U.S. Pat. No. 5,549,193 relates to an endless flexible seamed belt comprising puzzle cut members, wherein at least one receptacle has a substantial depth in a portion of the belt material at the belt ends.
U.S. Pat. No. 5,721,032 discloses a puzzle cut seamed belt having a strength-enhancing strip.
U.S. Pat. No. 5,487,707 discloses a puzzle cut seamed belt having a bond between adjacent surfaces, wherein an ultraviolet cured adhesive is used to bond the adjacent surfaces.
U.S. Pat. No. 5,514,436 relates to a puzzle cut seamed belt having a mechanically invisible seam, which is substantially equivalent in performance to a seamless belt.
U.S. Pat. No. 5,525,446 describes an intermediate transfer member including a base layer and top thermoplastic film forming polymer layer. The base layer can include a polycarbonate film, and the top layer can include polybutylenes. The belt can comprise an adhesive layer such as a polyvinylbutyral adhesive layer.
Embodiments of the present invention include: an endless seamed flexible belt comprising a first end and a second end, each of the first end and the second end comprising a plurality of mutually mating elements which join in an interlocking relationship to form a seam, the seam comprising an adhesive, and the belt comprising a substrate and an outer layer comprising a polyurethane derived from a polyvinylbutyral and isocyanate.
In addition, embodiments of the present invention include: an endless seamed flexible belt comprising a first end and a second end, each of the first end and the second end comprising a plurality of mutually mating elements which join in an interlocking relationship to form a seam, the belt comprising a polyimide substrate and an outer layer comprising a polyurethene derived from a polyvinylbutyral crosslinked with a block isocyanate.
Embodiments further include: an image forming apparatus for forming images on a recording medium comprising: a charge-retentive surface to receive an electrostatic latent image thereon; a development component to apply toner to the charge-retentive surface to develop the electrostatic latent image to form a developed image on the charge retentive surface; a transfer belt to transfer the developed image from the charge retentive surface to a copy substrate, wherein the transfer belt is an endless seamed flexible belt comprising a first end and a second end, each of the first end and the second end comprising a plurality of mutually mating elements which join in an interlocking relationship to form a seam, the transfer belt comprising a substrate and an outer layer comprising a polyurethane derived from polyvinylbutyral and isocyanate; and a fixing component to fuse the developed image to the copy substrate.